// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "bbpos.h"
#include "bkey_buf.h"
#include "btree_cache.h"
#include "btree_io.h"
#include "btree_iter.h"
#include "btree_locking.h"
#include "debug.h"
#include "errcode.h"
#include "error.h"
#include "journal.h"
#include "trace.h"
#include <linux/prefetch.h>
#include <linux/sched/mm.h>
#include <linux/swap.h>
#define BTREE_CACHE_NOT_FREED_INCREMENT(counter) \
do { \
if (shrinker_counter) \
bc->not_freed[BCH_BTREE_CACHE_NOT_FREED_##counter]++; \
} while (0)
const char * const bch2_btree_node_flags[] = {
#define x(f) #f,
BTREE_FLAGS()
#undef x
NULL
};
void bch2_recalc_btree_reserve(struct bch_fs *c)
{
unsigned reserve = 16;
if (!c->btree_roots_known[0].b)
reserve += 8;
for (unsigned i = 0; i < btree_id_nr_alive(c); i++) {
struct btree_root *r = bch2_btree_id_root(c, i);
if (r->b)
reserve += min_t(unsigned, 1, r->b->c.level) * 8;
}
c->btree_cache.nr_reserve = reserve;
}
static inline size_t btree_cache_can_free(struct btree_cache_list *list)
{
struct btree_cache *bc = container_of(list, struct btree_cache, live[list->idx]);
size_t can_free = list->nr;
if (!list->idx)
can_free = max_t(ssize_t, 0, can_free - bc->nr_reserve);
return can_free;
}
static void btree_node_to_freedlist(struct btree_cache *bc, struct btree *b)
{
if (b->c.lock.readers)
list_move(&b->list, &bc->freed_pcpu);
else
list_move(&b->list, &bc->freed_nonpcpu);
}
static void btree_node_data_free(struct bch_fs *c, struct btree *b)
{
struct btree_cache *bc = &c->btree_cache;
BUG_ON(btree_node_hashed(b));
/*
* This should really be done in slub/vmalloc, but we're using the
* kmalloc_large() path, so we're working around a slub bug by doing
* this here:
*/
if (b->data)
mm_account_reclaimed_pages(btree_buf_bytes(b) / PAGE_SIZE);
if (b->aux_data)
mm_account_reclaimed_pages(btree_aux_data_bytes(b) / PAGE_SIZE);
EBUG_ON(btree_node_write_in_flight(b));
clear_btree_node_just_written(b);
kvfree(b->data);
b->data = NULL;
#ifdef __KERNEL__
kvfree(b->aux_data);
#else
munmap(b->aux_data, btree_aux_data_bytes(b));
#endif
b->aux_data = NULL;
bc->nr_freeable--;
btree_node_to_freedlist(bc, b);
}
static int bch2_btree_cache_cmp_fn(struct rhashtable_compare_arg *arg,
const void *obj)
{
const struct btree *b = obj;
const u64 *v = arg->key;
return b->hash_val == *v ? 0 : 1;
}
static const struct rhashtable_params bch_btree_cache_params = {
.head_offset = offsetof(struct btree, hash),
.key_offset = offsetof(struct btree, hash_val),
.key_len = sizeof(u64),
.obj_cmpfn = bch2_btree_cache_cmp_fn,
.automatic_shrinking = true,
};
static int btree_node_data_alloc(struct bch_fs *c, struct btree *b, gfp_t gfp)
{
BUG_ON(b->data || b->aux_data);
gfp |= __GFP_ACCOUNT|__GFP_RECLAIMABLE;
b->data = kvmalloc(btree_buf_bytes(b), gfp);
if (!b->data)
return -BCH_ERR_ENOMEM_btree_node_mem_alloc;
#ifdef __KERNEL__
b->aux_data = kvmalloc(btree_aux_data_bytes(b), gfp);
#else
b->aux_data = mmap(NULL, btree_aux_data_bytes(b),
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
if (b->aux_data == MAP_FAILED)
b->aux_data = NULL;
#endif
if (!b->aux_data) {
kvfree(b->data);
b->data = NULL;
return -BCH_ERR_ENOMEM_btree_node_mem_alloc;
}
return 0;
}
static struct btree *__btree_node_mem_alloc(struct bch_fs *c, gfp_t gfp)
{
struct btree *b;
b = kzalloc(sizeof(struct btree), gfp);
if (!b)
return NULL;
bkey_btree_ptr_init(&b->key);
INIT_LIST_HEAD(&b->list);
INIT_LIST_HEAD(&b->write_blocked);
b->byte_order = ilog2(c->opts.btree_node_size);
return b;
}
struct btree *__bch2_btree_node_mem_alloc(struct bch_fs *c)
{
struct btree_cache *bc = &c->btree_cache;
struct btree *b;
b = __btree_node_mem_alloc(c, GFP_KERNEL);
if (!b)
return NULL;
if (btree_node_data_alloc(c, b, GFP_KERNEL)) {
kfree(b);
return NULL;
}
bch2_btree_lock_init(&b->c, 0);
bc->nr_freeable++;
list_add(&b->list, &bc->freeable);
return b;
}
void bch2_btree_node_to_freelist(struct bch_fs *c, struct btree *b)
{
mutex_lock(&c->btree_cache.lock);
list_move(&b->list, &c->btree_cache.freeable);
mutex_unlock(&c->btree_cache.lock);
six_unlock_write(&b->c.lock);
six_unlock_intent(&b->c.lock);
}
static inline bool __btree_node_pinned(struct btree_cache *bc, struct btree *b)
{
struct bbpos pos = BBPOS(b->c.btree_id, b->key.k.p);
u64 mask = bc->pinned_nodes_mask[!!b->c.level];
return ((mask & BIT_ULL(b->c.btree_id)) &&
bbpos_cmp(bc->pinned_nodes_start, pos) < 0 &&
bbpos_cmp(bc->pinned_nodes_end, pos) >= 0);
}
void bch2_node_pin(struct bch_fs *c, struct btree *b)
{
struct btree_cache *bc = &c->btree_cache;
mutex_lock(&bc->lock);
BUG_ON(!__btree_node_pinned(bc, b));
if (b != btree_node_root(c, b) && !btree_node_pinned(b)) {
set_btree_node_pinned(b);
list_move(&b->list, &bc->live[1].list);
bc->live[0].nr--;
bc->live[1].nr++;
}
mutex_unlock(&bc->lock);
}
void bch2_btree_cache_unpin(struct bch_fs *c)
{
struct btree_cache *bc = &c->btree_cache;
struct btree *b, *n;
mutex_lock(&bc->lock);
c->btree_cache.pinned_nodes_mask[0] = 0;
c->btree_cache.pinned_nodes_mask[1] = 0;
list_for_each_entry_safe(b, n, &bc->live[1].list, list) {
clear_btree_node_pinned(b);
list_move(&b->list, &bc->live[0].list);
bc->live[0].nr++;
bc->live[1].nr--;
}
mutex_unlock(&bc->lock);
}
/* Btree in memory cache - hash table */
void bch2_btree_node_hash_remove(struct btree_cache *bc, struct btree *b)
{
lockdep_assert_held(&bc->lock);
int ret = rhashtable_remove_fast(&bc->table, &b->hash, bch_btree_cache_params);
BUG_ON(ret);
/* Cause future lookups for this node to fail: */
b->hash_val = 0;
if (b->c.btree_id < BTREE_ID_NR)
--bc->nr_by_btree[b->c.btree_id];
bc->live[btree_node_pinned(b)].nr--;
bc->nr_freeable++;
list_move(&b->list, &bc->freeable);
}
int __bch2_btree_node_hash_insert(struct btree_cache *bc, struct btree *b)
{
BUG_ON(b->hash_val);
b->hash_val = btree_ptr_hash_val(&b->key);
int ret = rhashtable_lookup_insert_fast(&bc->table, &b->hash,
bch_btree_cache_params);
if (ret)
return ret;
if (b->c.btree_id < BTREE_ID_NR)
bc->nr_by_btree[b->c.btree_id]++;
bool p = __btree_node_pinned(bc, b);
mod_bit(BTREE_NODE_pinned, &b->flags, p);
list_move_tail(&b->list, &bc->live[p].list);
bc->live[p].nr++;
bc->nr_freeable--;
return 0;
}
int bch2_btree_node_hash_insert(struct btree_cache *bc, struct btree *b,
unsigned level, enum btree_id id)
{
b->c.level = level;
b->c.btree_id = id;
mutex_lock(&bc->lock);
int ret = __bch2_btree_node_hash_insert(bc, b);
mutex_unlock(&bc->lock);
return ret;
}
void bch2_btree_node_update_key_early(struct btree_trans *trans,
enum btree_id btree, unsigned level,
struct bkey_s_c old, struct bkey_i *new)
{
struct bch_fs *c = trans->c;
struct btree *b;
struct bkey_buf tmp;
int ret;
bch2_bkey_buf_init(&tmp);
bch2_bkey_buf_reassemble(&tmp, c, old);
b = bch2_btree_node_get_noiter(trans, tmp.k, btree, level, true);
if (!IS_ERR_OR_NULL(b)) {
mutex_lock(&c->btree_cache.lock);
bch2_btree_node_hash_remove(&c->btree_cache, b);
bkey_copy(&b->key, new);
ret = __bch2_btree_node_hash_insert(&c->btree_cache, b);
BUG_ON(ret);
mutex_unlock(&c->btree_cache.lock);
six_unlock_read(&b->c.lock);
}
bch2_bkey_buf_exit(&tmp, c);
}
__flatten
static inline struct btree *btree_cache_find(struct btree_cache *bc,
const struct bkey_i *k)
{
u64 v = btree_ptr_hash_val(k);
return rhashtable_lookup_fast(&bc->table, &v, bch_btree_cache_params);
}
/*
* this version is for btree nodes that have already been freed (we're not
* reaping a real btree node)
*/
static int __btree_node_reclaim(struct bch_fs *c, struct btree *b, bool flush, bool shrinker_counter)
{
struct btree_cache *bc = &c->btree_cache;
int ret = 0;
lockdep_assert_held(&bc->lock);
wait_on_io:
if (b->flags & ((1U << BTREE_NODE_dirty)|
(1U << BTREE_NODE_read_in_flight)|
(1U << BTREE_NODE_write_in_flight))) {
if (!flush) {
if (btree_node_dirty(b))
BTREE_CACHE_NOT_FREED_INCREMENT(dirty);
else if (btree_node_read_in_flight(b))
BTREE_CACHE_NOT_FREED_INCREMENT(read_in_flight);
else if (btree_node_write_in_flight(b))
BTREE_CACHE_NOT_FREED_INCREMENT(write_in_flight);
return -BCH_ERR_ENOMEM_btree_node_reclaim;
}
/* XXX: waiting on IO with btree cache lock held */
bch2_btree_node_wait_on_read(b);
bch2_btree_node_wait_on_write(b);
}
if (!six_trylock_intent(&b->c.lock)) {
BTREE_CACHE_NOT_FREED_INCREMENT(lock_intent);
return -BCH_ERR_ENOMEM_btree_node_reclaim;
}
if (!six_trylock_write(&b->c.lock)) {
BTREE_CACHE_NOT_FREED_INCREMENT(lock_write);
goto out_unlock_intent;
}
/* recheck under lock */
if (b->flags & ((1U << BTREE_NODE_read_in_flight)|
(1U << BTREE_NODE_write_in_flight))) {
if (!flush) {
if (btree_node_read_in_flight(b))
BTREE_CACHE_NOT_FREED_INCREMENT(read_in_flight);
else if (btree_node_write_in_flight(b))
BTREE_CACHE_NOT_FREED_INCREMENT(write_in_flight);
goto out_unlock;
}
six_unlock_write(&b->c.lock);
six_unlock_intent(&b->c.lock);
goto wait_on_io;
}
if (btree_node_noevict(b)) {
BTREE_CACHE_NOT_FREED_INCREMENT(noevict);
goto out_unlock;
}
if (btree_node_write_blocked(b)) {
BTREE_CACHE_NOT_FREED_INCREMENT(write_blocked);
goto out_unlock;
}
if (btree_node_will_make_reachable(b)) {
BTREE_CACHE_NOT_FREED_INCREMENT(will_make_reachable);
goto out_unlock;
}
if (btree_node_dirty(b)) {
if (!flush) {
BTREE_CACHE_NOT_FREED_INCREMENT(dirty);
goto out_unlock;
}
/*
* Using the underscore version because we don't want to compact
* bsets after the write, since this node is about to be evicted
* - unless btree verify mode is enabled, since it runs out of
* the post write cleanup:
*/
if (bch2_verify_btree_ondisk)
bch2_btree_node_write(c, b, SIX_LOCK_intent,
BTREE_WRITE_cache_reclaim);
else
__bch2_btree_node_write(c, b,
BTREE_WRITE_cache_reclaim);
six_unlock_write(&b->c.lock);
six_unlock_intent(&b->c.lock);
goto wait_on_io;
}
out:
if (b->hash_val && !ret)
trace_and_count(c, btree_cache_reap, c, b);
return ret;
out_unlock:
six_unlock_write(&b->c.lock);
out_unlock_intent:
six_unlock_intent(&b->c.lock);
ret = -BCH_ERR_ENOMEM_btree_node_reclaim;
goto out;
}
static int btree_node_reclaim(struct bch_fs *c, struct btree *b, bool shrinker_counter)
{
return __btree_node_reclaim(c, b, false, shrinker_counter);
}
static int btree_node_write_and_reclaim(struct bch_fs *c, struct btree *b)
{
return __btree_node_reclaim(c, b, true, false);
}
static unsigned long bch2_btree_cache_scan(struct shrinker *shrink,
struct shrink_control *sc)
{
struct btree_cache_list *list = shrink->private_data;
struct btree_cache *bc = container_of(list, struct btree_cache, live[list->idx]);
struct bch_fs *c = container_of(bc, struct bch_fs, btree_cache);
struct btree *b, *t;
unsigned long nr = sc->nr_to_scan;
unsigned long can_free = 0;
unsigned long freed = 0;
unsigned long touched = 0;
unsigned i, flags;
unsigned long ret = SHRINK_STOP;
bool trigger_writes = atomic_long_read(&bc->nr_dirty) + nr >= list->nr * 3 / 4;
if (bch2_btree_shrinker_disabled)
return SHRINK_STOP;
mutex_lock(&bc->lock);
flags = memalloc_nofs_save();
/*
* It's _really_ critical that we don't free too many btree nodes - we
* have to always leave ourselves a reserve. The reserve is how we
* guarantee that allocating memory for a new btree node can always
* succeed, so that inserting keys into the btree can always succeed and
* IO can always make forward progress:
*/
can_free = btree_cache_can_free(list);
nr = min_t(unsigned long, nr, can_free);
i = 0;
list_for_each_entry_safe(b, t, &bc->freeable, list) {
/*
* Leave a few nodes on the freeable list, so that a btree split
* won't have to hit the system allocator:
*/
if (++i <= 3)
continue;
touched++;
if (touched >= nr)
goto out;
if (!btree_node_reclaim(c, b, true)) {
btree_node_data_free(c, b);
six_unlock_write(&b->c.lock);
six_unlock_intent(&b->c.lock);
freed++;
bc->nr_freed++;
}
}
restart:
list_for_each_entry_safe(b, t, &list->list, list) {
touched++;
if (btree_node_accessed(b)) {
clear_btree_node_accessed(b);
bc->not_freed[BCH_BTREE_CACHE_NOT_FREED_access_bit]++;
--touched;;
} else if (!btree_node_reclaim(c, b, true)) {
bch2_btree_node_hash_remove(bc, b);
freed++;
btree_node_data_free(c, b);
bc->nr_freed++;
six_unlock_write(&b->c.lock);
six_unlock_intent(&b->c.lock);
if (freed == nr)
goto out_rotate;
} else if (trigger_writes &&
btree_node_dirty(b) &&
!btree_node_will_make_reachable(b) &&
!btree_node_write_blocked(b) &&
six_trylock_read(&b->c.lock)) {
list_move(&list->list, &b->list);
mutex_unlock(&bc->lock);
__bch2_btree_node_write(c, b, BTREE_WRITE_cache_reclaim);
six_unlock_read(&b->c.lock);
if (touched >= nr)
goto out_nounlock;
mutex_lock(&bc->lock);
goto restart;
}
if (touched >= nr)
break;
}
out_rotate:
if (&t->list != &list->list)
list_move_tail(&list->list, &t->list);
out:
mutex_unlock(&bc->lock);
out_nounlock:
ret = freed;
memalloc_nofs_restore(flags);
trace_and_count(c, btree_cache_scan, sc->nr_to_scan, can_free, ret);
return ret;
}
static unsigned long bch2_btree_cache_count(struct shrinker *shrink,
struct shrink_control *sc)
{
struct btree_cache_list *list = shrink->private_data;
if (bch2_btree_shrinker_disabled)
return 0;
return btree_cache_can_free(list);
}
void bch2_fs_btree_cache_exit(struct bch_fs *c)
{
struct btree_cache *bc = &c->btree_cache;
struct btree *b, *t;
unsigned long flags;
shrinker_free(bc->live[1].shrink);
shrinker_free(bc->live[0].shrink);
/* vfree() can allocate memory: */
flags = memalloc_nofs_save();
mutex_lock(&bc->lock);
if (c->verify_data)
list_move(&c->verify_data->list, &bc->live[0].list);
kvfree(c->verify_ondisk);
for (unsigned i = 0; i < btree_id_nr_alive(c); i++) {
struct btree_root *r = bch2_btree_id_root(c, i);
if (r->b)
list_add(&r->b->list, &bc->live[0].list);
}
list_for_each_entry_safe(b, t, &bc->live[1].list, list)
bch2_btree_node_hash_remove(bc, b);
list_for_each_entry_safe(b, t, &bc->live[0].list, list)
bch2_btree_node_hash_remove(bc, b);
list_for_each_entry_safe(b, t, &bc->freeable, list) {
BUG_ON(btree_node_read_in_flight(b) ||
btree_node_write_in_flight(b));
btree_node_data_free(c, b);
}
BUG_ON(!bch2_journal_error(&c->journal) &&
atomic_long_read(&c->btree_cache.nr_dirty));
list_splice(&bc->freed_pcpu, &bc->freed_nonpcpu);
list_for_each_entry_safe(b, t, &bc->freed_nonpcpu, list) {
list_del(&b->list);
six_lock_exit(&b->c.lock);
kfree(b);
}
mutex_unlock(&bc->lock);
memalloc_nofs_restore(flags);
for (unsigned i = 0; i < ARRAY_SIZE(bc->nr_by_btree); i++)
BUG_ON(bc->nr_by_btree[i]);
BUG_ON(bc->live[0].nr);
BUG_ON(bc->live[1].nr);
BUG_ON(bc->nr_freeable);
if (bc->table_init_done)
rhashtable_destroy(&bc->table);
}
int bch2_fs_btree_cache_init(struct bch_fs *c)
{
struct btree_cache *bc = &c->btree_cache;
struct shrinker *shrink;
unsigned i;
int ret = 0;
ret = rhashtable_init(&bc->table, &bch_btree_cache_params);
if (ret)
goto err;
bc->table_init_done = true;
bch2_recalc_btree_reserve(c);
for (i = 0; i < bc->nr_reserve; i++)
if (!__bch2_btree_node_mem_alloc(c))
goto err;
list_splice_init(&bc->live[0].list, &bc->freeable);
mutex_init(&c->verify_lock);
shrink = shrinker_alloc(0, "%s-btree_cache", c->name);
if (!shrink)
goto err;
bc->live[0].shrink = shrink;
shrink->count_objects = bch2_btree_cache_count;
shrink->scan_objects = bch2_btree_cache_scan;
shrink->seeks = 2;
shrink->private_data = &bc->live[0];
shrinker_register(shrink);
shrink = shrinker_alloc(0, "%s-btree_cache-pinned", c->name);
if (!shrink)
goto err;
bc->live[1].shrink = shrink;
shrink->count_objects = bch2_btree_cache_count;
shrink->scan_objects = bch2_btree_cache_scan;
shrink->seeks = 8;
shrink->private_data = &bc->live[1];
shrinker_register(shrink);
return 0;
err:
return -BCH_ERR_ENOMEM_fs_btree_cache_init;
}
void bch2_fs_btree_cache_init_early(struct btree_cache *bc)
{
mutex_init(&bc->lock);
for (unsigned i = 0; i < ARRAY_SIZE(bc->live); i++) {
bc->live[i].idx = i;
INIT_LIST_HEAD(&bc->live[i].list);
}
INIT_LIST_HEAD(&bc->freeable);
INIT_LIST_HEAD(&bc->freed_pcpu);
INIT_LIST_HEAD(&bc->freed_nonpcpu);
}
/*
* We can only have one thread cannibalizing other cached btree nodes at a time,
* or we'll deadlock. We use an open coded mutex to ensure that, which a
* cannibalize_bucket() will take. This means every time we unlock the root of
* the btree, we need to release this lock if we have it held.
*/
void bch2_btree_cache_cannibalize_unlock(struct btree_trans *trans)
{
struct bch_fs *c = trans->c;
struct btree_cache *bc = &c->btree_cache;
if (bc->alloc_lock == current) {
trace_and_count(c, btree_cache_cannibalize_unlock, trans);
bc->alloc_lock = NULL;
closure_wake_up(&bc->alloc_wait);
}
}
int bch2_btree_cache_cannibalize_lock(struct btree_trans *trans, struct closure *cl)
{
struct bch_fs *c = trans->c;
struct btree_cache *bc = &c->btree_cache;
struct task_struct *old;
old = NULL;
if (try_cmpxchg(&bc->alloc_lock, &old, current) || old == current)
goto success;
if (!cl) {
trace_and_count(c, btree_cache_cannibalize_lock_fail, trans);
return -BCH_ERR_ENOMEM_btree_cache_cannibalize_lock;
}
closure_wait(&bc->alloc_wait, cl);
/* Try again, after adding ourselves to waitlist */
old = NULL;
if (try_cmpxchg(&bc->alloc_lock, &old, current) || old == current) {
/* We raced */
closure_wake_up(&bc->alloc_wait);
goto success;
}
trace_and_count(c, btree_cache_cannibalize_lock_fail, trans);
return -BCH_ERR_btree_cache_cannibalize_lock_blocked;
success:
trace_and_count(c, btree_cache_cannibalize_lock, trans);
return 0;
}
static struct btree *btree_node_cannibalize(struct bch_fs *c)
{
struct btree_cache *bc = &c->btree_cache;
struct btree *b;
for (unsigned i = 0; i < ARRAY_SIZE(bc->live); i++)
list_for_each_entry_reverse(b, &bc->live[i].list, list)
if (!btree_node_reclaim(c, b, false))
return b;
while (1) {
for (unsigned i = 0; i < ARRAY_SIZE(bc->live); i++)
list_for_each_entry_reverse(b, &bc->live[i].list, list)
if (!btree_node_write_and_reclaim(c, b))
return b;
/*
* Rare case: all nodes were intent-locked.
* Just busy-wait.
*/
WARN_ONCE(1, "btree cache cannibalize failed\n");
cond_resched();
}
}
struct btree *bch2_btree_node_mem_alloc(struct btree_trans *trans, bool pcpu_read_locks)
{
struct bch_fs *c = trans->c;
struct btree_cache *bc = &c->btree_cache;
struct list_head *freed = pcpu_read_locks
? &bc->freed_pcpu
: &bc->freed_nonpcpu;
struct btree *b, *b2;
u64 start_time = local_clock();
mutex_lock(&bc->lock);
/*
* We never free struct btree itself, just the memory that holds the on
* disk node. Check the freed list before allocating a new one:
*/
list_for_each_entry(b, freed, list)
if (!btree_node_reclaim(c, b, false)) {
list_del_init(&b->list);
goto got_node;
}
b = __btree_node_mem_alloc(c, GFP_NOWAIT|__GFP_NOWARN);
if (!b) {
mutex_unlock(&bc->lock);
bch2_trans_unlock(trans);
b = __btree_node_mem_alloc(c, GFP_KERNEL);
if (!b)
goto err;
mutex_lock(&bc->lock);
}
bch2_btree_lock_init(&b->c, pcpu_read_locks ? SIX_LOCK_INIT_PCPU : 0);
BUG_ON(!six_trylock_intent(&b->c.lock));
BUG_ON(!six_trylock_write(&b->c.lock));
got_node:
/*
* btree_free() doesn't free memory; it sticks the node on the end of
* the list. Check if there's any freed nodes there:
*/
list_for_each_entry(b2, &bc->freeable, list)
if (!btree_node_reclaim(c, b2, false)) {
swap(b->data, b2->data);
swap(b->aux_data, b2->aux_data);
btree_node_to_freedlist(bc, b2);
six_unlock_write(&b2->c.lock);
six_unlock_intent(&b2->c.lock);
goto got_mem;
}
mutex_unlock(&bc->lock);
if (btree_node_data_alloc(c, b, GFP_NOWAIT|__GFP_NOWARN)) {
bch2_trans_unlock(trans);
if (btree_node_data_alloc(c, b, GFP_KERNEL|__GFP_NOWARN))
goto err;
}
mutex_lock(&bc->lock);
bc->nr_freeable++;
got_mem:
mutex_unlock(&bc->lock);
BUG_ON(btree_node_hashed(b));
BUG_ON(btree_node_dirty(b));
BUG_ON(btree_node_write_in_flight(b));
out:
b->flags = 0;
b->written = 0;
b->nsets = 0;
b->sib_u64s[0] = 0;
b->sib_u64s[1] = 0;
b->whiteout_u64s = 0;
bch2_btree_keys_init(b);
set_btree_node_accessed(b);
bch2_time_stats_update(&c->times[BCH_TIME_btree_node_mem_alloc],
start_time);
int ret = bch2_trans_relock(trans);
if (unlikely(ret)) {
bch2_btree_node_to_freelist(c, b);
return ERR_PTR(ret);
}
return b;
err:
mutex_lock(&bc->lock);
/* Try to cannibalize another cached btree node: */
if (bc->alloc_lock == current) {
b2 = btree_node_cannibalize(c);
clear_btree_node_just_written(b2);
bch2_btree_node_hash_remove(bc, b2);
if (b) {
swap(b->data, b2->data);
swap(b->aux_data, b2->aux_data);
btree_node_to_freedlist(bc, b2);
six_unlock_write(&b2->c.lock);
six_unlock_intent(&b2->c.lock);
} else {
b = b2;
list_del_init(&b->list);
}
mutex_unlock(&bc->lock);
trace_and_count(c, btree_cache_cannibalize, trans);
goto out;
}
mutex_unlock(&bc->lock);
return ERR_PTR(-BCH_ERR_ENOMEM_btree_node_mem_alloc);
}
/* Slowpath, don't want it inlined into btree_iter_traverse() */
static noinline struct btree *bch2_btree_node_fill(struct btree_trans *trans,
struct btree_path *path,
const struct bkey_i *k,
enum btree_id btree_id,
unsigned level,
enum six_lock_type lock_type,
bool sync)
{
struct bch_fs *c = trans->c;
struct btree_cache *bc = &c->btree_cache;
struct btree *b;
if (unlikely(level >= BTREE_MAX_DEPTH)) {
int ret = bch2_fs_topology_error(c, "attempting to get btree node at level %u, >= max depth %u",
level, BTREE_MAX_DEPTH);
return ERR_PTR(ret);
}
if (unlikely(!bkey_is_btree_ptr(&k->k))) {
struct printbuf buf = PRINTBUF;
bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(k));
int ret = bch2_fs_topology_error(c, "attempting to get btree node with non-btree key %s", buf.buf);
printbuf_exit(&buf);
return ERR_PTR(ret);
}
if (unlikely(k->k.u64s > BKEY_BTREE_PTR_U64s_MAX)) {
struct printbuf buf = PRINTBUF;
bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(k));
int ret = bch2_fs_topology_error(c, "attempting to get btree node with too big key %s", buf.buf);
printbuf_exit(&buf);
return ERR_PTR(ret);
}
/*
* Parent node must be locked, else we could read in a btree node that's
* been freed:
*/
if (path && !bch2_btree_node_relock(trans, path, level + 1)) {
trace_and_count(c, trans_restart_relock_parent_for_fill, trans, _THIS_IP_, path);
return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_fill_relock));
}
b = bch2_btree_node_mem_alloc(trans, level != 0);
if (bch2_err_matches(PTR_ERR_OR_ZERO(b), ENOMEM)) {
if (!path)
return b;
trans->memory_allocation_failure = true;
trace_and_count(c, trans_restart_memory_allocation_failure, trans, _THIS_IP_, path);
return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_fill_mem_alloc_fail));
}
if (IS_ERR(b))
return b;
bkey_copy(&b->key, k);
if (bch2_btree_node_hash_insert(bc, b, level, btree_id)) {
/* raced with another fill: */
/* mark as unhashed... */
b->hash_val = 0;
mutex_lock(&bc->lock);
list_add(&b->list, &bc->freeable);
mutex_unlock(&bc->lock);
six_unlock_write(&b->c.lock);
six_unlock_intent(&b->c.lock);
return NULL;
}
set_btree_node_read_in_flight(b);
six_unlock_write(&b->c.lock);
if (path) {
u32 seq = six_lock_seq(&b->c.lock);
/* Unlock before doing IO: */
six_unlock_intent(&b->c.lock);
bch2_trans_unlock_noassert(trans);
bch2_btree_node_read(trans, b, sync);
int ret = bch2_trans_relock(trans);
if (ret)
return ERR_PTR(ret);
if (!sync)
return NULL;
if (!six_relock_type(&b->c.lock, lock_type, seq))
b = NULL;
} else {
bch2_btree_node_read(trans, b, sync);
if (lock_type == SIX_LOCK_read)
six_lock_downgrade(&b->c.lock);
}
return b;
}
static noinline void btree_bad_header(struct bch_fs *c, struct btree *b)
{
struct printbuf buf = PRINTBUF;
if (c->curr_recovery_pass <= BCH_RECOVERY_PASS_check_allocations)
return;
prt_printf(&buf,
"btree node header doesn't match ptr\n"
"btree %s level %u\n"
"ptr: ",
bch2_btree_id_str(b->c.btree_id), b->c.level);
bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
prt_printf(&buf, "\nheader: btree %s level %llu\n"
"min ",
bch2_btree_id_str(BTREE_NODE_ID(b->data)),
BTREE_NODE_LEVEL(b->data));
bch2_bpos_to_text(&buf, b->data->min_key);
prt_printf(&buf, "\nmax ");
bch2_bpos_to_text(&buf, b->data->max_key);
bch2_fs_topology_error(c, "%s", buf.buf);
printbuf_exit(&buf);
}
static inline void btree_check_header(struct bch_fs *c, struct btree *b)
{
if (b->c.btree_id != BTREE_NODE_ID(b->data) ||
b->c.level != BTREE_NODE_LEVEL(b->data) ||
!bpos_eq(b->data->max_key, b->key.k.p) ||
(b->key.k.type == KEY_TYPE_btree_ptr_v2 &&
!bpos_eq(b->data->min_key,
bkey_i_to_btree_ptr_v2(&b->key)->v.min_key)))
btree_bad_header(c, b);
}
static struct btree *__bch2_btree_node_get(struct btree_trans *trans, struct btree_path *path,
const struct bkey_i *k, unsigned level,
enum six_lock_type lock_type,
unsigned long trace_ip)
{
struct bch_fs *c = trans->c;
struct btree_cache *bc = &c->btree_cache;
struct btree *b;
bool need_relock = false;
int ret;
EBUG_ON(level >= BTREE_MAX_DEPTH);
retry:
b = btree_cache_find(bc, k);
if (unlikely(!b)) {
/*
* We must have the parent locked to call bch2_btree_node_fill(),
* else we could read in a btree node from disk that's been
* freed:
*/
b = bch2_btree_node_fill(trans, path, k, path->btree_id,
level, lock_type, true);
need_relock = true;
/* We raced and found the btree node in the cache */
if (!b)
goto retry;
if (IS_ERR(b))
return b;
} else {
if (btree_node_read_locked(path, level + 1))
btree_node_unlock(trans, path, level + 1);
ret = btree_node_lock(trans, path, &b->c, level, lock_type, trace_ip);
if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
return ERR_PTR(ret);
BUG_ON(ret);
if (unlikely(b->hash_val != btree_ptr_hash_val(k) ||
b->c.level != level ||
race_fault())) {
six_unlock_type(&b->c.lock, lock_type);
if (bch2_btree_node_relock(trans, path, level + 1))
goto retry;
trace_and_count(c, trans_restart_btree_node_reused, trans, trace_ip, path);
return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_lock_node_reused));
}
/* avoid atomic set bit if it's not needed: */
if (!btree_node_accessed(b))
set_btree_node_accessed(b);
}
if (unlikely(btree_node_read_in_flight(b))) {
u32 seq = six_lock_seq(&b->c.lock);
six_unlock_type(&b->c.lock, lock_type);
bch2_trans_unlock(trans);
need_relock = true;
bch2_btree_node_wait_on_read(b);
ret = bch2_trans_relock(trans);
if (ret)
return ERR_PTR(ret);
/*
* should_be_locked is not set on this path yet, so we need to
* relock it specifically:
*/
if (!six_relock_type(&b->c.lock, lock_type, seq))
goto retry;
}
if (unlikely(need_relock)) {
ret = bch2_trans_relock(trans) ?:
bch2_btree_path_relock_intent(trans, path);
if (ret) {
six_unlock_type(&b->c.lock, lock_type);
return ERR_PTR(ret);
}
}
prefetch(b->aux_data);
for_each_bset(b, t) {
void *p = (u64 *) b->aux_data + t->aux_data_offset;
prefetch(p + L1_CACHE_BYTES * 0);
prefetch(p + L1_CACHE_BYTES * 1);
prefetch(p + L1_CACHE_BYTES * 2);
}
if (unlikely(btree_node_read_error(b))) {
six_unlock_type(&b->c.lock, lock_type);
return ERR_PTR(-BCH_ERR_btree_node_read_error);
}
EBUG_ON(b->c.btree_id != path->btree_id);
EBUG_ON(BTREE_NODE_LEVEL(b->data) != level);
btree_check_header(c, b);
return b;
}
/**
* bch2_btree_node_get - find a btree node in the cache and lock it, reading it
* in from disk if necessary.
*
* @trans: btree transaction object
* @path: btree_path being traversed
* @k: pointer to btree node (generally KEY_TYPE_btree_ptr_v2)
* @level: level of btree node being looked up (0 == leaf node)
* @lock_type: SIX_LOCK_read or SIX_LOCK_intent
* @trace_ip: ip of caller of btree iterator code (i.e. caller of bch2_btree_iter_peek())
*
* The btree node will have either a read or a write lock held, depending on
* the @write parameter.
*
* Returns: btree node or ERR_PTR()
*/
struct btree *bch2_btree_node_get(struct btree_trans *trans, struct btree_path *path,
const struct bkey_i *k, unsigned level,
enum six_lock_type lock_type,
unsigned long trace_ip)
{
struct bch_fs *c = trans->c;
struct btree *b;
int ret;
EBUG_ON(level >= BTREE_MAX_DEPTH);
b = btree_node_mem_ptr(k);
/*
* Check b->hash_val _before_ calling btree_node_lock() - this might not
* be the node we want anymore, and trying to lock the wrong node could
* cause an unneccessary transaction restart:
*/
if (unlikely(!c->opts.btree_node_mem_ptr_optimization ||
!b ||
b->hash_val != btree_ptr_hash_val(k)))
return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip);
if (btree_node_read_locked(path, level + 1))
btree_node_unlock(trans, path, level + 1);
ret = btree_node_lock(trans, path, &b->c, level, lock_type, trace_ip);
if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
return ERR_PTR(ret);
BUG_ON(ret);
if (unlikely(b->hash_val != btree_ptr_hash_val(k) ||
b->c.level != level ||
race_fault())) {
six_unlock_type(&b->c.lock, lock_type);
if (bch2_btree_node_relock(trans, path, level + 1))
return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip);
trace_and_count(c, trans_restart_btree_node_reused, trans, trace_ip, path);
return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_lock_node_reused));
}
if (unlikely(btree_node_read_in_flight(b))) {
six_unlock_type(&b->c.lock, lock_type);
return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip);
}
prefetch(b->aux_data);
for_each_bset(b, t) {
void *p = (u64 *) b->aux_data + t->aux_data_offset;
prefetch(p + L1_CACHE_BYTES * 0);
prefetch(p + L1_CACHE_BYTES * 1);
prefetch(p + L1_CACHE_BYTES * 2);
}
/* avoid atomic set bit if it's not needed: */
if (!btree_node_accessed(b))
set_btree_node_accessed(b);
if (unlikely(btree_node_read_error(b))) {
six_unlock_type(&b->c.lock, lock_type);
return ERR_PTR(-BCH_ERR_btree_node_read_error);
}
EBUG_ON(b->c.btree_id != path->btree_id);
EBUG_ON(BTREE_NODE_LEVEL(b->data) != level);
btree_check_header(c, b);
return b;
}
struct btree *bch2_btree_node_get_noiter(struct btree_trans *trans,
const struct bkey_i *k,
enum btree_id btree_id,
unsigned level,
bool nofill)
{
struct bch_fs *c = trans->c;
struct btree_cache *bc = &c->btree_cache;
struct btree *b;
int ret;
EBUG_ON(level >= BTREE_MAX_DEPTH);
if (c->opts.btree_node_mem_ptr_optimization) {
b = btree_node_mem_ptr(k);
if (b)
goto lock_node;
}
retry:
b = btree_cache_find(bc, k);
if (unlikely(!b)) {
if (nofill)
goto out;
b = bch2_btree_node_fill(trans, NULL, k, btree_id,
level, SIX_LOCK_read, true);
/* We raced and found the btree node in the cache */
if (!b)
goto retry;
if (IS_ERR(b) &&
!bch2_btree_cache_cannibalize_lock(trans, NULL))
goto retry;
if (IS_ERR(b))
goto out;
} else {
lock_node:
ret = btree_node_lock_nopath(trans, &b->c, SIX_LOCK_read, _THIS_IP_);
if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
return ERR_PTR(ret);
BUG_ON(ret);
if (unlikely(b->hash_val != btree_ptr_hash_val(k) ||
b->c.btree_id != btree_id ||
b->c.level != level)) {
six_unlock_read(&b->c.lock);
goto retry;
}
}
/* XXX: waiting on IO with btree locks held: */
__bch2_btree_node_wait_on_read(b);
prefetch(b->aux_data);
for_each_bset(b, t) {
void *p = (u64 *) b->aux_data + t->aux_data_offset;
prefetch(p + L1_CACHE_BYTES * 0);
prefetch(p + L1_CACHE_BYTES * 1);
prefetch(p + L1_CACHE_BYTES * 2);
}
/* avoid atomic set bit if it's not needed: */
if (!btree_node_accessed(b))
set_btree_node_accessed(b);
if (unlikely(btree_node_read_error(b))) {
six_unlock_read(&b->c.lock);
b = ERR_PTR(-BCH_ERR_btree_node_read_error);
goto out;
}
EBUG_ON(b->c.btree_id != btree_id);
EBUG_ON(BTREE_NODE_LEVEL(b->data) != level);
btree_check_header(c, b);
out:
bch2_btree_cache_cannibalize_unlock(trans);
return b;
}
int bch2_btree_node_prefetch(struct btree_trans *trans,
struct btree_path *path,
const struct bkey_i *k,
enum btree_id btree_id, unsigned level)
{
struct bch_fs *c = trans->c;
struct btree_cache *bc = &c->btree_cache;
BUG_ON(path && !btree_node_locked(path, level + 1));
BUG_ON(level >= BTREE_MAX_DEPTH);
struct btree *b = btree_cache_find(bc, k);
if (b)
return 0;
b = bch2_btree_node_fill(trans, path, k, btree_id,
level, SIX_LOCK_read, false);
if (!IS_ERR_OR_NULL(b))
six_unlock_read(&b->c.lock);
return bch2_trans_relock(trans) ?: PTR_ERR_OR_ZERO(b);
}
void bch2_btree_node_evict(struct btree_trans *trans, const struct bkey_i *k)
{
struct bch_fs *c = trans->c;
struct btree_cache *bc = &c->btree_cache;
struct btree *b;
b = btree_cache_find(bc, k);
if (!b)
return;
BUG_ON(b == btree_node_root(trans->c, b));
wait_on_io:
/* not allowed to wait on io with btree locks held: */
/* XXX we're called from btree_gc which will be holding other btree
* nodes locked
*/
__bch2_btree_node_wait_on_read(b);
__bch2_btree_node_wait_on_write(b);
btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_intent);
btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_write);
if (unlikely(b->hash_val != btree_ptr_hash_val(k)))
goto out;
if (btree_node_dirty(b)) {
__bch2_btree_node_write(c, b, BTREE_WRITE_cache_reclaim);
six_unlock_write(&b->c.lock);
six_unlock_intent(&b->c.lock);
goto wait_on_io;
}
BUG_ON(btree_node_dirty(b));
mutex_lock(&bc->lock);
bch2_btree_node_hash_remove(bc, b);
btree_node_data_free(c, b);
mutex_unlock(&bc->lock);
out:
six_unlock_write(&b->c.lock);
six_unlock_intent(&b->c.lock);
}
const char *bch2_btree_id_str(enum btree_id btree)
{
return btree < BTREE_ID_NR ? __bch2_btree_ids[btree] : "(unknown)";
}
void bch2_btree_id_to_text(struct printbuf *out, enum btree_id btree)
{
if (btree < BTREE_ID_NR)
prt_str(out, __bch2_btree_ids[btree]);
else
prt_printf(out, "(unknown btree %u)", btree);
}
void bch2_btree_pos_to_text(struct printbuf *out, struct bch_fs *c, const struct btree *b)
{
prt_printf(out, "%s level %u/%u\n ",
bch2_btree_id_str(b->c.btree_id),
b->c.level,
bch2_btree_id_root(c, b->c.btree_id)->level);
bch2_bkey_val_to_text(out, c, bkey_i_to_s_c(&b->key));
}
void bch2_btree_node_to_text(struct printbuf *out, struct bch_fs *c, const struct btree *b)
{
struct bset_stats stats;
memset(&stats, 0, sizeof(stats));
bch2_btree_keys_stats(b, &stats);
prt_printf(out, "l %u ", b->c.level);
bch2_bpos_to_text(out, b->data->min_key);
prt_printf(out, " - ");
bch2_bpos_to_text(out, b->data->max_key);
prt_printf(out, ":\n"
" ptrs: ");
bch2_val_to_text(out, c, bkey_i_to_s_c(&b->key));
prt_newline(out);
prt_printf(out,
" format: ");
bch2_bkey_format_to_text(out, &b->format);
prt_printf(out,
" unpack fn len: %u\n"
" bytes used %zu/%zu (%zu%% full)\n"
" sib u64s: %u, %u (merge threshold %u)\n"
" nr packed keys %u\n"
" nr unpacked keys %u\n"
" floats %zu\n"
" failed unpacked %zu\n",
b->unpack_fn_len,
b->nr.live_u64s * sizeof(u64),
btree_buf_bytes(b) - sizeof(struct btree_node),
b->nr.live_u64s * 100 / btree_max_u64s(c),
b->sib_u64s[0],
b->sib_u64s[1],
c->btree_foreground_merge_threshold,
b->nr.packed_keys,
b->nr.unpacked_keys,
stats.floats,
stats.failed);
}
static void prt_btree_cache_line(struct printbuf *out, const struct bch_fs *c,
const char *label, size_t nr)
{
prt_printf(out, "%s\t", label);
prt_human_readable_u64(out, nr * c->opts.btree_node_size);
prt_printf(out, " (%zu)\n", nr);
}
static const char * const bch2_btree_cache_not_freed_reasons_strs[] = {
#define x(n) #n,
BCH_BTREE_CACHE_NOT_FREED_REASONS()
#undef x
NULL
};
void bch2_btree_cache_to_text(struct printbuf *out, const struct btree_cache *bc)
{
struct bch_fs *c = container_of(bc, struct bch_fs, btree_cache);
if (!out->nr_tabstops)
printbuf_tabstop_push(out, 32);
prt_btree_cache_line(out, c, "live:", bc->live[0].nr);
prt_btree_cache_line(out, c, "pinned:", bc->live[1].nr);
prt_btree_cache_line(out, c, "freeable:", bc->nr_freeable);
prt_btree_cache_line(out, c, "dirty:", atomic_long_read(&bc->nr_dirty));
prt_printf(out, "cannibalize lock:\t%p\n", bc->alloc_lock);
prt_newline(out);
for (unsigned i = 0; i < ARRAY_SIZE(bc->nr_by_btree); i++)
prt_btree_cache_line(out, c, bch2_btree_id_str(i), bc->nr_by_btree[i]);
prt_newline(out);
prt_printf(out, "freed:\t%zu\n", bc->nr_freed);
prt_printf(out, "not freed:\n");
for (unsigned i = 0; i < ARRAY_SIZE(bc->not_freed); i++)
prt_printf(out, " %s\t%llu\n",
bch2_btree_cache_not_freed_reasons_strs[i], bc->not_freed[i]);
}
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